package com.wbt.jdk.lock;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * @program:
 * @description:
 * @author: Wang·Baotong
 * @create: 2021-03-23 12:36
 */
public class ReadWriteLockDemo {
    public static void main(String[] args) {
       // MyCache myCache = new MyCache();
        MyCacheLock myCache = new MyCacheLock();
        // 写入
        for (int i = 1; i <= 5 ; i++) {
            final int temp = i;

            new Thread(()->{ myCache.get(temp+""); },String.valueOf(i)).start();

            new Thread(()->{
                myCache.put(temp+"",temp+"");
            },String.valueOf(i)).start();

        }
        // 读取
        for (int i = 1; i <= 5 ; i++) {
            final int temp = i;

        }
    }
}

// 加锁的
class MyCacheLock{
    private volatile Map<String,Object> map = new HashMap<>(); // 读写锁： 更加细粒度的控制
    private ReadWriteLock readWriteLock = new ReentrantReadWriteLock(); private Lock lock = new ReentrantLock();
    // 存，写入的时候，只希望同时只有一个线程写
    public void put(String key,Object value){
        readWriteLock.writeLock().lock();
        try {
            TimeUnit.SECONDS.sleep(5);

            System.out.println(Thread.currentThread().getName()+"写入"+key);
            map.put(key,value);
            System.out.println(Thread.currentThread().getName()+"写入OK");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            readWriteLock.writeLock().unlock();
        }
    }
    // 取，读，所有人都可以读！
    public void get(String key){
        readWriteLock.readLock().lock();
        try {
            System.out.println(Thread.currentThread().getName()+"读取"+key);
            Object o = map.get(key);
            System.out.println(Thread.currentThread().getName()+"读取OK" + o.toString() );
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            readWriteLock.readLock().unlock();
        }
    }
}

class MyCacheLock1{
    private volatile Map<String,Object> map = new HashMap<>(); // 读写锁： 更加细粒度的控制
    //private Lock readWriteLock = new ReentrantLock();
    private Lock lock = new ReentrantLock();
    // 存，写入的时候，只希望同时只有一个线程写
    public void put(String key,Object value){
        lock.lock();
        try {

            TimeUnit.SECONDS.sleep(5);

            System.out.println(Thread.currentThread().getName()+"写入"+key);
            map.put(key,value);
            System.out.println(Thread.currentThread().getName()+"写入OK");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    // 取，读，所有人都可以读！
    public void get(String key){

        System.out.println(Thread.currentThread().getName()+"读取"+key);
        Object o = map.get(key);
        System.out.println(Thread.currentThread().getName()+"读取OK," + o.toString());

    }
}

/*** 自定义缓存 */

class MyCache{
    private volatile Map<String,Object> map = new HashMap<>();
    // 存，写
    public void put(String key,Object value){
        System.out.println(Thread.currentThread().getName()+"写入"+key);
        map.put(key,value);
        System.out.println(Thread.currentThread().getName()+"写入OK");
    }
    // 取，读
    public void get(String key){
        System.out.println(Thread.currentThread().getName()+"读取"+key);
        Object o = map.get(key);
        System.out.println(Thread.currentThread().getName()+"读取OK，" + o.toString());
    }
}